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United States Patent | 5,644,916 |
Hayasaki | July 8, 1997 |
A hydraulic pressure supply system for a variable torque transfer of a four-wheel drive vehicle in which a driving-torque distribution ratio between front and rear road wheels is varied by adjusting a clutch pressure applied to a variable torque clutch assembled in said transfer, comprises an oil pressure source supplying a pressurized working fluid into a hydraulic line, at least one pressure regulating valve fluidly connected to the line for decreasingly regulating the pressurized working fluid at a predetermined clutch pressure, and a directional control valve fluidly connected to the pressure regulating valve for directing the clutch pressure to a transfer clutch. An electromagnetic solenoid valve is provided for controlling the pressure regulating valve and the directional control valve for selectively supplying one of a stand-by pressure and a clutch engaging pressure to the transfer clutch. The stand-by pressure is set to be slightly less than a predetermined pressure level at which the transfer clutch starts to engage.
Inventors: | Hayasaki; Koichi (Ebina, JP) |
Assignee: | Nissan Motor Co., Ltd. (Yokohama, JP) |
Appl. No.: | 320544 |
Filed: | October 11, 1994 |
Nov 02, 1993[JP] | 5-274238 | |
Nov 30, 1993[JP] | 5-300666 |
Current U.S. Class: | 60/436; 60/437; 192/109F |
Intern'l Class: | F16D 031/02 |
Field of Search: | 60/428,437,435,436 91/19,33,446,28,31,32 192/109 F 180/247 |
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3135168 | Jun., 1964 | Rutherford | 91/446. |
3188916 | Jun., 1965 | Beatty | 91/446. |
3576241 | Apr., 1971 | Maurice et al. | 91/31. |
3741360 | Jun., 1973 | Patton | 60/428. |
4711318 | Dec., 1987 | Kitade | 180/247. |
4792012 | Dec., 1988 | Morisawa et al. | 180/247. |
4891942 | Jan., 1990 | Schwarz | 60/436. |
4915189 | Apr., 1990 | Sakai | 180/247. |
4915190 | Apr., 1990 | Iwata | 180/247. |
5010974 | Apr., 1991 | Matsuda | 180/247. |
Foreign Patent Documents | |||
58-193907 | Nov., 1983 | JP | 91/446. |
2-68225 | Mar., 1990 | JP. |